This application claims the benefit of Korean No. 2001-59498, filed Sep. 26, 2001, in the Korean Industrial Property office, the disclosure of which is incorporated herein by reference.
1. Field of the Invention
The present invention relates to an image forming apparatus, such as a laser printer, and more particularly, to a paper discharging device of an image forming apparatus discharging printed sheets of paper in a zigzag fashion.
2. Description of the Related Art
A laser printer is one of typical image forming apparatuses that are mainly connected to a network or a computer to print desired information page by page. Compared to a dot printer or an inkjet printer, the laser printer uses an electrophotography printing method by which the laser printer projects a laser beam to an electrically charged photosensitive mechanism, forms an electrostatic latent image, develops the electrostatic latent image to a visible image by toner particles, and transfers and fixes the developed visible image on printing paper.
Generally, the laser printer comprises a paper cassette, a developing unit, a stacker, and a discharging unit.
In the laser printer, paper picked-up from the paper cassette is supplied to the developing unit. After being printed in the developing unit, the paper passes through the discharging unit and is stacked on the stacker.
The paper that is printing-finished through a series of the above-described processes is stacked in the stacker in printing order. Conventionally, the laser printer continuously discharges all sheets of the paper to the same position of the stacker. Therefore, there is a problem in that a user is required to classify the sheets of the paper one by one. Also, when the user prints the same image on a number of sheets, it is more disadvantageous for the user to classify all of the sheets one by one. Therefore, there is inconvenience in directly and additionally classifying all of the sheets manually one by one and also there is a loss of time.
The present invention is developed in order to solve the above problems, and an object of the present invention is to provide a paper discharging device of an image forming apparatus capable of more simply and economically discharging printing paper in a zigzag fashion.
Additional objects and advantageous of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.
The above and other objects are accomplished by providing a paper discharging device comprising a rotary shaft rotating by a driving power of a driving source, a hollow shaft into which the rotary shaft is slidably inserted, the hollow shaft rotating in association with the rotary shaft and reciprocating along the rotary shaft, a driving shaft disposed at a predetermined distance from and in parallel to the rotary shaft to rotate in association with the rotary shaft, a driving gear installed on an end of the rotary shaft, a driven gear rotatably disposed at the driving shaft and engaged with the driving gear, an electrical clutch selectively transmitting the rotating force of the driven gear to the driving shaft, and a reciprocating unit reciprocating the hollow shaft in accordance with a rotation of the driving shaft.
Meanwhile, the paper discharging device further comprises a holding cam disposed at an end of the driving shaft, a pivoting lever pressingly contacting the holding cam to restrict a rotation of the driving shaft, and a spring biasing the pivoting lever toward the holding cam, and a reciprocating unit detecting the rotation of the driving shaft.
The reciprocating unit comprises a guide block connected to an end of the hollow shaft and connected to a guide rail at a lower side thereof, the guide block reciprocating along the guide rail so as to reciprocate the hollow shaft along the rotary shaft, a guide cam disposed at the driving shaft and having a spiral guide groove formed on an outer circumference thereof, and a guide lever with one end hinged to an upper surface of the guide block and with the other end inserted into the guide groove.
The detecting unit comprises a photo sensor and a sensing lever coaxially combined with the pivoting lever and rotating bilaterally in association with the pivoting lever so as to selectively block and permit transmission of light which is transmitted from a light emitting portion of the photo sensor to a light receiving portion of the photo sensor.
According to the paper discharging device, by the reciprocal movement of the hollow shaft connected to a rotary roller, paper is discharged obliquely toward a left portion or a right portion of a stacker to be discharged one by one in a zigzag fashion.